I would not go with it as a way of obtaining sneak attack damage. 4E is balanced such that rogues are largely expected to get their sneak attack damage every round, anyway, and there are easier ways to get sneak attack via powers, flanking, and stealth checks than taking a -10 to hit - unless the additional called shot damage stacked on top of *that*, it would be pretty lame.

I like the "take -10 to hit for an auto-crit" idea better. I don't know that I'd say the game is balanced around players only hitting 50% of the time - many of the pure Strikers in my game are regularly attaining odds a lot better than that. My barbarian hits your typical brute/minion/artillery on something like a 7+, generally.

Keep in mind, though, that critical hits often trigger other features. Take the barbarian as an example: in addition to possibly wielding a weapon that does additional damage on a crit (both via magical item property or simply being a high-crit weapon), he gets to follow that up with another melee basic attack. Assuming he kills his target (which to be frank is pretty damn likely at that point), he can potentially follow that up with a charge.

As your players get higher level, the number of class- and feat- based mechanics that are triggered on critical hits only grows, and abilities like Righteous Brand/Lance of Faith can set up situations that offset that Called Shot to a great degree. This isn't to say it's a BAD idea (players smart enough to stack bonuses up to a point where Called Shots have some likelihood to hit should be rewarded!), but really think through the size of the penalty and make sure it's offsetting the potentially massive benefits they may reap for getting a critical hit. Given how easy it is to crank your attack bonus up really high for a single attack and/or get attack rerolls/multiple rolls/adjust roles you don't like (e.g. Oath of Enmity, the barbarian power Combat Surge, the Deva and Elf racial powers, the human feat Action Surge, etc), this seems like it could have some consequences you don't intend. It's not hard to envision a situation in which a striker spends an AP, gets a solid leader bonus power, uses a multiple roll/reroll a miss ability, etc. until he's practically guaranteed that crit, possibly on a 3W or 4W damage power. Then he scores a ton of extra damage, your cleric pops a channel divinity power that triggers on a crit, etc. I think there's a reason why even at epic tier a lot of strikers are still only critting at on a 19 or 20!

Finally, it's also worth noting that like most abilities that reward getting lucky on dice rolls, it can seriously wreak havoc on your players if monsters get access to it, too. That solo who's designed to hit your fighter ~70% of the time will have absolutely no trouble making called shots against the wizard 60% of the time, if not more often. An auto-crit or two could literally knock him unconscious and/or accidentally kill him before anybody has a chance to help him out. If your players are doing that to monsters, you can always add an extra monster to future encounters...if that happens to the party's wizard, they're buying a resurrection or he's rolling up a new character.

Anyway, don't mean to take the wind out of your sails, just pointing out some concerns. It's a really interesting idea and now that you've mentioned it, I'm considering it as an environmental/terrain power for some upcoming encounters in my campaign (my players are only level 2, and in early heroic tier I'm a big fan of giving players options besides "ok, encounter powers are gone, everyone spam at-wills at the monsters until they're dead"). I just think it has a lot of implications - particularly as Strikers get more and more abilities that ensure their hits will land - to think through before I'd roll it out as a general house rule for my campaign.

Great thoughts everyone. So I think I like the idea of making this a feat the best. There has been alot of feedback that -10 is too high. I haven't heard any objections to my -5 idea. -5 to hit and score a crit. I like the blinding/dazing/stunning, etc. idea. Then we need a suitable drawback. I would love to make it take longer than normal. Any thoughts on how to make it take longer than a standard?

If you're gonna make it a feat, I'd say make it a -4 to hit-- double the penalty from power attack, and on a hit, it dazes the foe until the start of your next turn-- no crit, because then you get into all sorts of problems, as Branar noted That still might be broken though, but here are the benefits and drawbacks as I see them:

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1. Dazing is powerful, especially at will.

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1. It doesn't do weapon damage.
2. -4 is a hefty penalty.
3. They are only dazed until start of your next turn, not end.

If the feat is called shot maybe it should have optional effects. Ie called shot is -4 to roll. But you get the option to daze (aim for the head) slow (aim for the feet) cause them to take a penalty to their next attack (air for their weapon arm).. etc...

Haven't considered the balance implications of these effects but you get the idea.

Edit: reread the thread and noticed I managed to skip a whole bunch of posts. Some of these ideas already been stated though I think sticking to the existing conditions is the best way to keep the mechanic from becoming a chore to keep track of.

Edit2: I'd be very cautious over allowing it with all at-wills until you had done a good look over all the at-will powers to find out how broken it could be. Maybe basic attacks - though that could be too restrictive...

Edit3: Kind wish I had my books with me.. wondering if -2 and restricted to basic attacks might be a better balance.. but no way to check easily here. Don't even have the character builder.

i, too, also like the idea of a feat which allows a special "called shot" maneuver. -4 to hit, no damage, and a daze, is definitely okay. you might need to take 2 seperate feats though, once for melee attacks, once for ranged attacks, representing differences in training needed to accomplish the feat.

Hmmm, I'm trying to think of balance issues. I think most people would not take this feat. It might be too penalizing. Maybe no penalty to hit, or only a -1 or 2. Trading off a daze for damage with a -4 to hit might be weak.

It would seem that if you are giving up damage for a daze that ends at the start of your next turn, I think -4 to hit is pushing it.

At -2 to hit I'd grab this as a defender. Even more so if you allowed it to be added to Melee Basic Attacks granted through OA's. t would be a fantastic defender at-will. It helps lock down opponents and as a defender, you don't have to do a lot of damage but you'd be opening up CA to your party members left and right so they can do full damage.

So at -2, it might be too powerful for a defender to have access too! But, it would really help them do their job and make it easier for the strikers to do their jobs too.